At first, I was having trouble with a HTTP 301 error, but, after contacting the web service owners, they instructed me to change the endpoint to https. I did so by changing the ENDPOINT_ADDRESS_PROPERTY. I then started getting javax.xml.ws.soap.SOAPFaultException: MustUnderstand headers:[{http://www.w3.org/2005/08/addressing}Action] are not understood" exception. It was solving this exception that took me to the code I'll reproduce next and to the exception on the title.